Regulating resistance for electric currents.



No, 857,138y

- PATENTBD JUNE 18, 1907 P. WBBER.

REGULATING RESISTANGE FOR ELECTRIC GURRBNTS.

ATION FILED NOV. 20, 1906.

APPLIU i zen of the German Empire, and a resident of spondingly Cuxhaven, Germany, have invented certain l l gradually sucked through tion, and Fig. 2 represents a p pose. is to restrict the electric current to PAUL woEBEE, or CUXHAVEN, GERMANY.

FEGULATING RESISTANCE FOR ELECTRIC CURRENTS1 Speccatonv'of Letters Patent.

Patented June 18,1907.

Application iiled Nvembel' 20,1906 Serial No. 344,216.

To all whom it may concern:

bearing blocks m. A slide vblock ornut f is Beit known that I, PAUL WBEEE, a citimounted upon the spindle e, and. 1s correnew and useful Improvements in Regulating Resistances for Electric Currents, oi which the following is a specification.

The present invention has iorits object a regulating resistance Jor electric current,

which is particularly adapted for use in medical and especially dental practice, its pirt 1e smallest possible amount at the beginning and to increase the amount verygradually. To this end a non-conductor of an absorbent material is provided in the a paratus, one of its ends bemgimmersed in liquid, which is non-conductor, thereby gradually rendering it a conductor, and increasing 'th`e strength of the current in the Same proportion.

vThis apparatus is of great importance in dental practice, especially for eiecting cataphoresis and similar operations and aiso for all similar technical vpurposes where it is desirable to permit the electric current to become operative gradually by switching in the current as slowly and uniformly as possible. The known devices, which are preferably provided with nickel resistances have not succeeded in; complying with these conditions, because the current sup lied by them is always too powerful in the st place, and then increases in strength intermittently.

.These detects are obviated by means of the apparatus hereinafter described.

A constructional Jform of this apparatus is illustrated by way of example in the accom pany-ing drawing, in which Figure 1 represents the same in side eleva lan viewA The apparatus comprises t e switch board a, upon which the contacts b and c with terminal screws the conducting wires are arranged. To the contact b a screw spindle eis connected, this spindle ends in a handle 'L and is mounted in the whole of theb and c1 for the connection of screw-threaded. A rod d of wood or other non-conducting absorbent material is connected with the contact c, its.

extremity resting in a cavity where it is held by a spring 7L. A contact spring g 'fixed upon the slide f engages with the rod d. By rotating the handle i in one direction or the other, the contact spring g may be caused to slide forward or backward on the rod d.

When the apparatus is in use, the rod dais in the plate l,

withdrawn and one of its ends is immersed 1n 1. A device of the character described,

comprising a pair of contacts, an absorbent non-conducting rod connected to one of said contacts, a liquid element carried by said rod and means for metallically connecting said rod to the other contact, substantially as specified.

2. A device of. the character described, comprising a pair of contacts, an absorbent non-conducting rod connected to one of said -contacts, a li uid element carried by said rod a screw spindle connected to the other contact, anda slide movable on the spindle and adapted to engage specified.

Signed by me at Cuxhaven, Germany, this 31st day of October, 1906.

PAUL WOBBER. Witnesses:

PAUL THODE, 'GEORG HEINRICH.

the' rod, substantially as v 

